Regex Extraction Using a list of Words as reference , Python

Question

I have a list of prepositions in a txt file. I am creating a function such that it will extract the word following the prepositions from a string. Since there are many prepositions , it would not be feasible to directly put them into re.compile . So i am using a txt file. Here's my code :

with open("Input.txt"):
words = "|".join(line.rstrip() for line in open)
pattern = re.compile('{}\s(\w+|\d+\w+)\s\w+'.format(words))

where {} would represent match of preps ,whereas \s is a space followed by a word or a combination of digits and words like 20th cross and so on. The error i'm getting is

TypeError                                 Traceback (most recent call last)
<ipython-input-43-0aed517ef1ba> in <module>()
  1 with open("Input.txt"):
----> 2     words = "|".join(line.rsplit() for line in open)
  3 pattern = re.compile("{}\s(\w+|\d+\w+)\s\w+".format(words))

TypeError: 'builtin_function_or_method' object is not iterable

The Input.txt file has contents as ['near','above','towards'...] and so on.. how do i iterate over it??

falsetru · Accepted Answer · 2014-02-27 05:19:32Z

2

The code is iterating open function. You should interate the a file object to get lines.

And rsplit is seems like a typo of rstrip.

with open("Input.txt") as f:
    words = "|".join(line.rstrip() for line in f)
    pattern = re.compile(r'(?:{})\s(\w+|\d+\w+)\s\w+'.format(words))

In case word contains some character that has special meaning in regular expression, it should be escaped using re.escape.

with open("Input.txt") as f:
    words = "|".join(re.escape(line.rstrip()) for line in f)
    pattern = re.compile(r'(?:{})\s(\w+|\d+\w+)\s\w+'.format(words))

edited Feb 27, 2014 at 5:19

answered Feb 27, 2014 at 5:07

falsetru

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4 Comments

Hypothetical Ninja Over a year ago

i tried with re.search and it is extracting the wrong part . text3 = "coo1, renissance park one, near yeshwanthpur metro, near columbia asia hospital , on a road parallel to railway track." q = re.search(pattern,text3)

Hypothetical Ninja Over a year ago

hi, thanks but i want only the words following near to get extracted(or along with it).. i just want near yeshwantpur metro or near columbia asia

falsetru Over a year ago

@Sword, Could you post a separated question? (with content of the file, expected output, original text)

Hypothetical Ninja Over a year ago

stackoverflow.com/questions/22061087/…

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